Specimen Requirements

Container/Tube:

Preferred: Gold-top serum gel tube or plain, red-top tube-Plasma is not acceptable due to possible fibrin interaction yielding false positives.
Specimen Volume: 0.2 mL of serum

Stability: Samples may be stored up to 48 hours at 2-8º C, or frozen for prolonged storage. 
Collection Instructions: 
Note: 1. Specimens from patients who have received preparations of monoclonal antibodies for diagnosis or therapy may contain HAMA. Such specimens may cause false positive or false negative results.

2. False negative results may occur when the levels of hCG are below the sensitivity level of the test. When pregnancy is still suspected, a serum specimen should be collected 48 hours later and tested.

3. Very low levels of hCG (less than 50 mIU/mL) are present in serum shortly after implantation. However, because a significant number of first trimester pregnancies terminate for natural reasons, a test result that is weakly positive should be confirmed by retesting with a serum specimen collected 48 hours later.

4. A number of conditions other than pregnancy, including trophoblastic disease and certain nontrophoblastic neoplasms including testicular tumors, prostate cancer, breast cancer, and lung cancer, cause elevated levels of hCG. Therefore, the presence of hCG in serum should not be used to diagnose pregnancy unless these conditions have been ruled out.

5. This test provides a presumptive diagnosis for pregnancy. A confirmed pregnancy diagnosis should only be made by a physician after all clinical and laboratory findings have been evaluated.